On incoming calls I am receiving the error Unparsable SDP (code 28)
Phone version: Zoiper5 5.3.8 for Windows 64bit
Library revision: v2.9.30
Phone revision: 5.3.8_Windows
UI revision: 1.2.17
To test I loaded Microsip Portable on the same windows machine (same number and credentials) and the incoming calls work fine.
STUN Server: Off and On
Enabled all available codecs
Use rport: Off and ON
Use rport media: Off and ON
I also have the Zoiper debug from the last failed incoming call.